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The Optimal Design of TMD for Offshore Structures

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China ocean Engineering 1999年第2期14卷 133-144页

作者： Sau Lon James HU Tomotsuka TAKAYAMA dept. of ocean engrg. University of Rhode Island RI02881 Professor Professor Disaster Prevention Res. Inst. Kyoto Univ. Gokasho Uji Kyoto 611-0011 Japan.

This paper presents the optimal design procedure of Tuned Mass Damper (TMD) for reducing vibration of an actual steel jacket offshore platform excited by random wave loading. In this study, a frequency domain is taken. The force on the structure is determined by use of the linearized Morison equation for an input Power Spectral Density (PSD) of wave elevation. The sensitivity of optimum values of TMD to characteristic parameters of random wave spectrum is analyzed. An optimized TMD design for the modeled platform is given based on design conditions and the findings of the study.

关键词： tuned mass damper design Morison equation power spectral density offshore structures

Finite Element Analysis of soft Foundation Strengthening by Vacuum Loading from Lower Position

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China ocean Engineering 1997年第1期12卷 109-118页

作者： Qiu, CL Yan, SW dept. of Hydraulic engrg Tianjin University Tianjin 300072 China

Strengthening soft foundation by vacuum loading from lower position is a new method of accelerating the consolidation of dredger fill. This paper presents the mechanism of soft foundation strengthening by vacuum loading from lower position and evaluates the effectiveness of this method under various boundary conditions by means of finite element method (FEM) on the basis of Biot's consolidation theory.

关键词： soft foundation strengthening vacuum loading lower position FEM

Modulus of Subgrade Reaction for Laterally Loaded Piles in Multiple Layered Foundation

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China ocean Engineering 1997年第4期12卷 477-486页

作者： Lu Ziai Associate Professor, dept. of Navigation and ocean Engineering, Hohai University, Nanjing210024 dept. of Navigation and ocean Engineering Hohai University Nanjing 210024 China

According to the field test data of laterally loaded steel piles at home and abroad, an empirical formula for evaluating the modulus of subgrade reaction under static load in layered soil is proposed. The suggested formula takes account of not only non-linearity of K-s with the dept. but also its variation with the load. It is shown that the computed bending moments along the pile shaft and the deflection at the pile top are consistent with the measured ones.

关键词： modulus pile foundation formula deflection moment

Experimental Study on the Effects of A Breakwater on Wave Field Characteristics

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China ocean Engineering 2000年第2期15卷 229-242页

作者：尹彰周宗仁黄伟柏 ocean Engineering Laboratory Dept. of Harbour and River Eng. National Taiwan Ocean University 20224 Keelung Taiwan

Studies on the possible effects of a detached breakwater on the characteristics of the wave field are carried out experimentally. A serpentine wave generator is used to generate both uni- and multi- directional waves. Characteristics of the wave fields analyzed here include the wave field directionality, and the probability distributions of surface elevations and of the wave heights. Owing to the presence of the breakwater. waves outside the harbour are Found to be reflected with, however, concentrated energy within the harbour entrance. In general. wave heights can be approximated with a Rayleigh distribution, with occasional deviations from the theory. This occurs more frequently for waves with higher peak frequency values than for those with lower values both for uni- and multi-directional waves. Surface elevations can be approximated with the Gaussian model, although the Edgeworth's form of the type A Gram- Charlier series expansions would yield better fits. Wave directionality is found to have no discernible effects on the statistical characteristics of the wave field.

关键词： wave directionality statistical distributions surface elevations wave heights

Breaking of Solitary Waves on Uniform Slopes

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China ocean Engineering 1999年第4期14卷 429-442页

作者：周宗仁欧阳宽 dept. of Harbor and River Eng. Taiwan Ocean University Keelung Taiwan

The propagation, shoaling and breaking of solitary waves on mild slopes are simulated by boundary element method. In this paper, the criterion of breaking solitary waves on mild slopes is discussed. The criterion is that the ratio of horizontal velocity of water particles on the wave crest to wave celerity equals one. However, the case that the ratio of horizontal velocity of water particles on the wave crest to wave celerity is below one but the front face of wave profile becomes vertical is also considered as a breaking criterion. According to the above criteria, the breaking index for slopes 1:10 to 1:25 is studied. The result is compared to other researchers'. The deformation of solitary waves on slopes is discussed and the distribution of fluid velocities at breaking is shown.

关键词： breaking wave solitary wave distribution of fluid velocity boundary element

Design of variable structure controller for uncertain time-delay singular system

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Journal of Harbin Institute of Technology(New Series) 2009年第3期16卷 331-337页

作者：郭继峰高存臣 Science School Qingdao Technological University dept. of Mathematics Ocean University of China

To study the approximation theory of real sliding mode and the design of variable structure controller for time-invariant linear uncertain time-delay singular system,the approximation theory of real sliding mode was developed to provide foundation for obtaining sliding mode by equivalent control,and switching functions with integral dynamic compensators and variable structure controllers were designed respectively under two circumstances that the system without uncertain part was stabilized by delay-dependent and delay-independent linear state feedback. The design guarantees the asymptotical stablity of switching manifolds,and the variable structure controllers can force solution trajectory of the system to arrive at the switching manifolds in limited time. A numerical example is given to demonstrate the feasibility and simplicity of the design method.

关键词： singular system time-delay uncertain system : variable structure control

DYNAMICS OF MEDDIES INTERACTED WITH A SEAMOUNT IN A 1.5 LAYER MODEL

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Journal of Hydrodynamics 2001年第3期13卷 93-99页

作者： Luo, De-Hai Lu, Yan dept. of Atmosph. and oceanic Sci. Ocean Univ. of Qingdao Qingdao 266003 China

A simplified model is proposed to describe the interaction of meddies with a seamount. In the absence of topography, the meddy obtained in this model moves very slowly to the west. However, in the presence of Gaussian-shaped topography (seamount) the movement of the meddy is strongly controlled by its site. As the seamount is located in the southwest side of a meddy, this meddy will be induced to move southward. But if the seamount is located in the west side of the meddy, the seamount forcing will cause a southwest movement of such a meddy. For two meddies in the absence of seamount, the two meddies will be located on the northwest-southeast axis due to their interaction, which is the natural evolution of two anticyclonic eddies. However, the presence of a seamount will cause the meddies to merge rapidly. This merging is also influenced by the site of the seamount, the closer the seamount is to the two meddies, the faster the two meddies merge. In addition, the direction of the corotating two meddies in the northwest-southeast axis is also influenced by the site of the seamount.

关键词： Equations of motion Hydrodynamics Hydrographic surveys Multilayers Numerical analysis ocean currents

Intelligent learning technique based-on fuzzy logic for multi-robot path planning

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Journal of Harbin Institute of Technology(New Series) 2001年第3期8卷 222-227页

作者：孟庆春殷波熊建设魏天滨王旭柱王汝霖 dept. of Electron. Eng. Ocean Univ. of Qingdao Qingdao 266003 China

Soccer robot system is a tremendously challenging intelligent system developed to mimic human soccer competition based on the multi discipline research: robotics, intelligent control, computer vision, etc. robot path planning strategy is a very important subject concerning to the performance and intelligence degree of the multi robot system. Therefore, this paper studies the path planning strategy of soccer system by using fuzzy logic. After setting up two fuzziers and two sorts of fuzzy rules for soccer system, fuzzy logic is applied to workspace partition and path revision. The experiment results show that this technique can well enhance the performance and intelligence degree of the system.

关键词： fuzzy logic multi agent system intelligent system robot path planning

EXPERIMENTS OF HYDRODYNAMICS AND STABILITY OF IMMERSED TUBE TUNNEL ON TRANSPORTATION AND IMMERSING

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Journal of Hydrodynamics 2001年第2期13卷 121-126页

作者： Zhan, D.X. Wang, X.Q. dept. of Naval Arch. and ocean Eng. Wuhan Univ. of Technol. Wuhan 430063 China

Effects of environment conditions, such as current, wave etc., are more important for immersed tube tunnel's transportation and immersing. The hydrodynamics and stability of immersed tube tunnel during its towing and immersing are interested for departments of design and construction. A serial model tests are made in towing tank and water channel for Nanjing immersed tube tunnel, and the first immersed tunnel has been designed in Yangtzi River in China. The hydrodynamic forces and rope tensions of the tunnel are measured with strain balances when it is towed by ship and immersed by winches for a different current velocity and wave height. In addition, the stability of tunnel for a different ballast water is tested and discussed.

关键词： Hydrodynamics Stability Tensile testing Test facilities